msm: camera: isp: remove buffer queue traverse per irq

The bufferq list contains the whole buffer manager queues.
the traverse and matching is happening on every irq which
is expensive and does not have much value.

Remove this redundant list.

Change-Id: I489a4bcfbf01af9f450f39de6dbfe2e5bdb25c3a
Signed-off-by: Peter Liu <pingchie@codeaurora.org>